Yattaracer201

Hey folks,
I just picked up a used torsen differential from a 96 at the scrapyard the other day (car had been t-boned). Straight away, Pinion bearing preload is measuring 0 in-lbs (assembled with carrier). Note: differential appears to have been opened up before.
My question for you guys is what should I do with the pinion nut?? Leave it as is and assume it was fine in the previous car?
Tighten it to spec (which I am having trouble finding)?
Tighten it to only about 5 in lbs (since the diff is used)?
Take the nut off, replace it, and add lock tite; then proceed to tighten to a spec?
Any input is appreciated, thanks!